Potentiometric Surface of the Upper Floridan Aquifer in the Coastal Area of Georgia, September 2000

The Upper Floridan aquifer is part
of the Floridan aquifer system that underlies most of the Coastal Plain of
Georgia, southern South Carolina, extreme southeastern Alabama, and all of
Florida (Miller, 1986). The aquifer system is one of the most productive in
the United States and a major source of water in the coastal area of Georgia.
In 1997, approximately 347 million gallons per day (Mgal/d) of ground water
was withdrawn in coastal Georgia mainly for industrial and irrigation purposes
(Fanning, 1999).

This report shows the potentiometric
surface of the Upper Floridan aquifer in coastal Georgia for September 2000.
The potentiometric surface, which represents the altitude at which water would
have stood in tightly cased wells open to the Upper Floridan aquifer, was
constructed by using water-level and pressure measurements collected from
225 wells during September 2000. The distribution of data used to construct
the map is similar to a previously contoured map (Peck and others, 1999) with
the exception of the Jesup, Wayne County area. In this area, a cone of depression
has historically been present due to industrial pumping of about 63.9 Mgal/d (Fanning,
2003). During September 2000 however, water-level measurements were not obtained
in this area; therefore, the May 1998 surface (Peck and others, 1999) is shown
on an inset map.

This study was conducted as part
of the Georgia Department of Natural Resources, Environmental Protection Division's
Sound Science Initiative, a series of scientific and feasibility studies designed
to determine how to limit or reduce saltwater intrusion in coastal Georgia.
As part of this program, the U.S. Geological Survey (USGS), in cooperation
with the Environmental Protection Division (EPD), Georgia Geologic Survey
(GGS), is investigating the paths and rates of saltwater movement into the
Upper Floridan aquifer, determining other areas where saltwater contamination
could occur, assessing alternative sources of freshwater supplies, such as
the surficial and upper and lower Brunswick aquifers, and developing a monitoring
network to assess ground-water levels and quality.

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